#include <bits/stdc++.h>
#define ll long long
#define ull unsigned ll
#define pb push_back
#define pa pair<int, int>
#define pall pair<ll, int>
#define fi first
#define se second
#define TASK "test"
#define Size(x) (int) x.size()
#define all(x) x.begin(), x.end()
using namespace std;
template<typename T1, typename T2> bool mini (T1 &a, T2 b) {if(a > b) a = b; else return 0; return 1;}
template<typename T1, typename T2> bool maxi (T1 &a, T2 b) {if(a < b) a = b; else return 0; return 1;}
const int MOD = 1e9 + 7;
const int LOG = 20;
const int maxn = 2e5 + 7;
const ll oo = 1e18 + 69;
int n, q, s, t, a[maxn], l, r, x, type[maxn];
struct BIT {
ll bit[maxn];
void update(int x, ll val) {
for(; x <= n; x += x&-x) bit[x] += val;
}
ll get(int x) {
ll ans = 0;
for(; x; x -= x&-x) ans += bit[x];
return ans;
}
} bit[2];
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
//freopen(TASK".inp", "r", stdin);
//freopen(TASK".out", "w", stdout);
cin>>n>>q>>s>>t;
for(int i = 0; i <= n; i++) cin>>a[i];
for(int i = 1; i <= n; i++) {
type[i] = (a[i - 1] - a[i] >= 0);
bit[type[i]].update(i, a[i - 1] - a[i]);
}
while(q--) {
cin>>l>>r>>x;
ll val = bit[type[l]].get(l) - bit[type[l]].get(l - 1);
bit[type[l]].update(l, -val);
val -= x;
type[l] = (val >= 0);
bit[type[l]].update(l, val);
if(r < n) {
val = bit[type[r + 1]].get(r + 1) - bit[type[r + 1]].get(r);
bit[type[r + 1]].update(r + 1, -val);
val += x;
type[r + 1] = (val >= 0);
bit[type[r + 1]].update(r + 1, val);
}
cout<<bit[0].get(n) * s + bit[1].get(n) * t<<"\n";
}
return 0;
}
